let/Parent = "div"
let/Child = "a"
div/el
  svg
    -- $!{input.value}
    Child href="#bar" -- Hi

  math
    -- $!{input.value}
    Child href="#bar" -- Hi

  Parent --
    $!{input.value}

  button.toggle-parent onClick() {
    Parent = Parent === "div" ? "svg" : "div";
  } -- Toggle Parent

  button.toggle-child onClick() {
    Child = Child === "a" ? null : "a";
  } -- Toggle Child

script --
  Parent;
  Child;
  for (const node of el().querySelectorAll("a")) {
    if (node.getAttribute("ns") !== node.namespaceURI) {
      node.setAttribute("ns", node.namespaceURI!);
    }
  }
